1.\" $NetBSD: alarm.3,v 1.22 2003/08/07 16:42:45 agc Exp $ 2.\" 3.\" Copyright (c) 1980, 1991, 1993, 1994 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)alarm.3 8.2 (Berkeley) 4/19/94 31.\" 32.Dd April 19, 1994 33.Dt ALARM 3 34.Os 35.Sh NAME 36.Nm alarm 37.Nd set signal timer alarm 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In unistd.h 42.Ft unsigned int 43.Fn alarm "unsigned int seconds" 44.Sh DESCRIPTION 45.Bf -symbolic 46This interface is made obsolete by 47.Xr setitimer 2 . 48.Ef 49.Pp 50The 51.Fn alarm 52function sets a timer to deliver the signal 53.Dv SIGALRM 54to the calling process 55.Ar seconds 56after the call to 57.Fn alarm . 58If an alarm has already been set with 59.Fn alarm 60but has not been delivered, another call to 61.Fn alarm 62will supersede the prior call. 63The request 64.Fn alarm "0" 65voids the current 66alarm and the signal SIGALRM will not be delivered. 67The maximum number of 68.Ar seconds 69allowed 70is 2147483647. 71.Pp 72The return value of 73.Fn alarm 74is the amount of time left on the timer from a previous call to 75.Fn alarm . 76If no alarm is currently set, the return value is 0. 77If there is an error setting the timer, 78.Fn alarm 79returns ((unsigned int) -1). 80.Sh SEE ALSO 81.Xr setitimer 2 , 82.Xr sigaction 2 , 83.Xr sigsuspend 2 , 84.Xr signal 3 , 85.Xr sigvec 3 , 86.Xr sleep 3 , 87.Xr ualarm 3 , 88.Xr usleep 3 89.Sh STANDARDS 90The 91.Fn alarm 92function conforms to 93.St -p1003.1-90 . 94.Sh HISTORY 95An 96.Fn alarm 97function appeared in 98.At v7 . 99